1. Field of the Invention
The present invention relates to an X-ray imaging technique for preventing patients from being exposed to excessive doses of radiation.
2. Description of the Related Art
X-ray diagnostic imaging utilizing X-rays has typically been applied in radiographic interpretation using still images, although in recent years its application has expanded to include X-ray fluoroscopic examination and surgical support. However, X-ray fluoroscopic examination and surgical support, while being extremely beneficial, unavoidably expose patients to radiation, and the exposure risk must always be taken into consideration when performing X-ray diagnosis and surgical support. Despite these risks, the X-ray dose has heretofore typically been adjusted manually by the operator providing the medical care. The operator selects the appropriate X-ray dose, with regard to the surgical objective, examination application, examination site, the patient's physique, age and sex, the characteristics of the apparatus and so on. In the case of a procedure using fluorography, the operator prepares a surgical plan after manually calculating the X-ray dose.
Japanese Patent Laid-Open No. 2005-253801 proposes an X-ray diagnostic apparatus that estimates the cumulative exposure dose, and issues a warning and stops the irradiation when the estimated cumulative exposure dose reaches a prescribed limit. Further, Japanese Patent Laid-Open No. 2005-253801 proposes an X-ray diagnostic apparatus that estimates the cumulative exposure dose, works out the period for which irradiation is possible at the current X-ray irradiation dose per unit time based on the estimated cumulative exposure dose, and displays the result.
Overexposure can be avoided with conventional X-ray diagnostic apparatus that estimates the cumulative exposure dose, and issues a warning and stops the irradiation when the cumulative exposure dose reaches a prescribed dose. On the other hand, however, the scheduled procedure has to be aborted even though it may not have been completed. Even if the cumulative exposure dose is estimated and the period for which irradiation is possible at the current X-ray irradiation dose per unit time is worked out based on the cumulative exposure dose and displayed, the procedure either needs to be aborted or continued for longer than the displayed remaining period if the procedure has not ended within the remaining period.